Prefix –in means “not” or “without”Vertebra is one of the bones along the back of

an animalAn INVERTEBRATE is an animal without a

backboneMost animal species are invertebratesSkeleton – a structure in animals and humans

that provides mechanical support for muscle attachment and maintaining body shape

Although an invertebrate does not have a backbone, it does have a skeleton

It may have either an internal or external skeleton made of minerals similar to limestone, glass, protein, and even ordinary water

1. About how many animal species are there?

2. Why is a bee considered an invertebrate?

3. Besides bone, list three substances that could compose an animal's skeleton.

Sponges are “pore animals”Their existence depends on the number of pores

in their bodies through which they pump water that brings food and oxygen in and carries wastes out

Phylum PoriferaAll sponges live in the water, and most live in

oceansAdult sponges remain permanently attached to

solid objects and are unable to move place to place, BUT embryonic sponges can swim around briefly

Have skeletons made of spongin, of spicules, or of bothSpongin - is a flexible, fibrous proteinSpicules – stiff, pointed little spikes made of

calcium carbonate or silicaBe familiar with Figure 15B-1 on page 269Collar cells – cells lining the central cavity,

which possess flagellaSponges are often called filter feeders

because they filter water to obtain food

1. To what sponge characteristic does the name Porifera refer?

2. If adult sponges are permanently attached to solid objects, how can they colonize other areas?

3. What and how do sponges eat?

Jellyfish belong to the phylum CnidariaThey have tentacles with stinging cellsThey are usually found in oceans; though a few

can be found in freshwater15C.1 The Body of a Jellyfish

The Jellyfish has a hydrostatic skeleton.Has a large central cavity surrounded by two tissue

layers. Layers are called the ectoderm and the endoderm. Inside the endoderm is the gastrovascular cavity

were the Jellyfish digests its food.The Jellyfish has no brain, just a network of nerves.

15C.2 Jellyfish Activities

The Jellyfish can defend itself and paralyze its prey with nematocysts (special cells found in the ectoderm).

The Jellyfish uses weak fiber muscle fibers in its tentacles to push the prey into its gastrovascular cavity.

Digestive enzymes are released by cells in the endoderm to break down the food in the gastrovascular cavity.

Jellyfish do not use their tentacles to swim. Most of the time jellyfish just float.

When they do swim, a set of muscle fibers around the rim of the jellyfish contracts.

15C.3 Other Interesting Cnidarians

Hydras, corals, and sea anemones are also cnidarians.

The Portuguese man-of-war is a dangerous cnidarian that is actually a floating colony containing many specialized polyps.

The bodies of cnidarians have radial symmetry.Radial symmetry means that they can be

divided into equal halves by any plane along the length of the organism.

Cnidarians may be either free-floating or permanently attached to a solid object.

1. What is the supporting material in a jellyfish's skeleton?

2. Where do jellyfish digest their prey?3. What is the soft body of a coral animal called?

Flatworm members = flat!Bilateral symmetry (can be divided into two

equal halves – like a mirror image)Phylum Platyhelminthes It is a free-living (not a parasite) flatworm that

can be found in freshwater streams and in soil.Flatworms can be found in the oceans, in fresh

water inside other animals as parasites, or in the soil.

15D.1 The Planarian’s Nervous SystemNeurons are long, thin nerve cells found

throughout the body of an animal or human.Most animals control their bodies through

neurons.A collection of neurons wrapped in protective

coverings is called a nerve.Many invertebrates have nervous systems that

are fairly complex and require some coordination. An invertebrate’s “coordination center” is a ganglion, sometimes called a simple brain.

15D.1 The Planarian’s Nervous SystemThe planarian has a simple nervous system. A

longitudinal nerve runs down each side of its body.

A series of transverse nerves connects the longitudinal nerves.

The planarian’s ganglia coordinate its responses to stimuli.

A stimulus is something an organism can sense. Planarians respond differently to different

things such as touch, the flow of water, chemicals in water, and light.

15D.2 The Planarian’s Digestive and Excretory Systems.

The planarian’s body covering is a tissue that is one cell-layer thick.

Cilia on the underside of the planarian help it glide over underwater surfaces.

The mouth of he planarian is on its underside, near the middle of its body.

Just inside the mouth is a long branching cavity called the intestine which is lined with a layer of cells which is called the gastroderm.

The planarian eats by extending a muscular tube called the pharanx through the mouth and sucking food into the intestine.

15D.2 The Planarian’s Digestive and Excretory Systems.

The planarian’s food is digested in the gastroderm.Nondigestible material is pushed out of the intestine

though the mouth.The planarian’s intestines extend to every area of the

worm’s body and food is moved throughout the intestine by the twisting movements of the planarian and by flagella.

The planarian has a mass of cells between its body covering and gastroderm. Some of the cells are specialized for particular functions.

The planarian’s body is very thin. This allows the animal’s cells to exchange oxygen and carbon dioxide directly with the environment.

15D.2 The Planarian’s Digestive and Excretory Systems.

The planarian gets rid of its waste products through a system of tiny tubes.

At the end of these tubes are structures called flame cells. The cilia at the end of these structures look like tiny flames.

These cilia move water and wastes through the tubes to tiny holes called excretory pores. Here the water and wastes are excreted from the planarian.

15D.3 Other Interesting FlatwormsSome other common flatworms include

tapeworms, flukes and marine flateworms.Tapeworms (a common parasite of animals

and humans) are found in the digestive tracts of various animals.

A Tapeworm has a head equipped with hooks and/or suckers to attach it securely to the digestive tract. It is nourished by absorbing dissolved food that is passing through this digestive cavity.

1. What type of symmetry does a planarian have?

2. How many longitudinal nerves does a planarian have?

3. Where is the mouth of a planarian?

15E.1 Ascaris – A Common RoundwormIn the phylum Nematoda Have round, tubular bodies and are tapered

at each endSome are serious parasites of humans,

animals, and plants; others are free-livingMany are microscopic; some may grow to be

30cm (12in) long!The adult Ascaris can be found in the

intestines of various animals

15E.1 Ascaris – A Common RoundwormThe tiny eggs are swallowed and young

larvae burrow in the intestine walls and enter the blood stream

They eventually reach the lungs and travel up the throat and are reswallowed

In the intestine again, larvae develop into adults

Humans, cats, dogs, and various farm animals can have round worms

15E.2 Other Interesting RoundwormsOther serious roundworm parasites include

hookworms, pinworms, and trichina wormsTrichina often form cysts containing larvae in

the muscle tissue of pigsVinegar eel – appear as tiny threads in

unpasteurized vinegar and cider products (not parasitic thankfully!)

Other roundworms cause serious plant diseases

1. Name the phylum that includes roundworms2. Where does an adult Ascaris normally live?3. Are roundworms parasites of animals only?

Explain.

15F Segmented WormsThe earthworm has a long, slender body

made of a series of similar segmentsThe segmented body plan is what

distinguishes earthworms from othersPhylum AnnelidaLeeches, tube worms, scale worms,

sandworms, and fireworms also belong to this group

15F.1 The Body of an EarthwormCovering the earthworm’s body is a thin, skin

called an epidermisThe epidermis exchanges gases (carbon

dioxide and oxygen) with the environment.It also secretes a thin outer coating called the

cuticleThe cuticle protects the earthworm from

harmful parasites and substancesCuticle must be thin and its epidermis kept

moist for gas exchange

15F.1 The Body of an EarthwormUnder the epidermis, are two muscle layersThey provide support and help it moveOne layer is arranged in circles around the

earthworm’s bodyWhen these muscles contract, the worm becomes

longer and thinnerThe other muscle layer is arranged in long strips

running from the head to the tailWhen these muscles contract, the earthworm

becomes shorter and wider

15F.1 The Body of an EarthwormThe earthworm moves by using its muscles and

tiny bristles on each segmentIt moves forward by extending the bristles on its

rear segments into the soilOnce the rear segments are anchored, it contracts

its circular muscles – which causes it to become long and thin, pushing its front end forward

Then the worm releases the rear segments and extend the front half into the soil, pulling itself forward by contracting its long muscles

15F.2 The Earthworm’s Nervous SystemThere are many sensory receptors on the body of the

earthwormSensory receptor – a structure that can sense a

stimulus and then start an impulse traveling along a neuron

Some of its sensory receptors are sensitive to chemicals in the soil, others to light, and some to temperature and other conditions

There are more sensory receptors at an earthworm’s front end because it leads with its front end

They help the worm to sense whether it is approaching food or danger so that it can react accordingly

15F.2 The Earthworm’s Nervous SystemThe earthworm’s neurons carry impulses from

the sensory receptors in the front of the worm to two large ganglia in the third segment

Sensory receptors in other areas send impulses to the nerve cord in the lower half of the worm

Nerve cord – a bundle of neurons that begins at the two large ganglia and continues to the tail of the worm

Along the nerve cord there is one small ganglion in each segment of the worm

15F.2 The Earthworm’s Nervous SystemThe ganglia interpret the impulses from the

sensory receptors, and the worm decides what to do with them

Interprets and decides describe the worm’s response to stimuli – but these words are not good words because they imply intelligence

Earthworms have very little intelligenceNeurons carry impulses to muscles, bristles, and

other structures that will enable the earthworm to respond properly

15F.3 The Earthworm’s Digestive Systemoften eats the soil as it forms tunnelsMost of the soil is indigestible, but within the soil are

decaying leaves, fungi, and small creaturesHas a long, straight digestive tractAt various points along the tract, there are

enlargements, constrictions, infoldings, and glandsEach has a separate functionThe mouth secretes fluids that moisten the soil as it

entersLook closely: you may notice an upper lip! Used to

force food in their mouth

15F.3 The Earthworm’s Digestive SystemFrom the mouth, the soil passes to the pharynxThen to the esophagus – a tubular passageway that

carries food from the pharynx to the cropCrop – looks like a swelling in the digestive tractFood leaving the crop passes into the gizzard –

another bulge in the digestive tractThen it goes from the gizzard to the intestineIndigestible parts pass through the intestine and

leave the digestive tract through the anusCastings – wastes that accumulate in piles outside the

tunnels

15F.4 The Earthworm’s Circulatory SystemA continuous network of blood vesselsClosed Circulatory System – when blood never leaves

the blood vesselsDorsal blood vessel – along the back – acts as a heartIt pumps blood forward to the five sets of aortic archesVentral blood vessel carries blood throughout wormCapillaries – blood passes through arteries and enter

tiny blood vessels called capillariesBlood flows from arteries through capillaries to veinsIn closed systems, blood is carried toward the heart

15F.4 The Earthworm’s Circulatory System

Path of blood flow in a closed circulatory system:Veins heart

arteries capillaries Veins

15F.5 The Earthworm’s Respiratory and Excretory System

Does not have special respiratory structuresGas exchange through the moist skinExcretory tubules – where wastes collect an are

passed out of the body through tiny pores

1. Name three members of phylum Annelida besides earthworms

2. In which part of the earthworm's digestive system does mechanical digestion occur

3. How does an earthworm breathe?4. How can our study of earthworms help us

exercise dominion over the earth?

Mollusks include the following animals:ClamsSnailsSlugsOctopuses

Phylum MolluscaPhylum with the 2nd highest number of species

and is very important to the environmentAlso important to man

Food (clams, oysters, and scallops)Make things (pearls, mother-of-pearl

buttons)Pests or parasites (slugs and snails can be

pests)

It’s body lacks structure to give it firm support

It does have many muscles Eight arms (tentacles) that

has muscle to help it move its arms in any direction

On the underside of each arm, there are suction disks, which allow it to grasp items.

Food captured in its arms can be moved to its mouth (located under the head)

The suction disks can also be used to fasten itself to things

If an arm is destroyed or severed, it has the ability to regenerate (grow) a replacement!

Although it hunts live food (crabs, lobsters, and shelled mollusks), it appears to be a timid animal

If it senses danger, it hides It moves by gliding along in the water – but it is a

slow creature In order to move quickly, it forces water through a

muscular tube called a siphonThis jets the octopus through the waterOccasionally, when frightened, it will release an inky

black fluid into the water to serve as a “smoke screen”, allowing it to get away.

The octopus has a thin, flexible skin that helps its body hide more easily in the cracks between rocks and the ocean floor

It can “pour itself” into gaps and completely change its body shape

It can also cause different colored cells on their skin to spread out their pigments, helping to change colors!

It can become visible against almost any background

Its colors may also reflect its level of stimulation If it is startled, it usually turns pale; when it is

excited, it often turns red

It produces a shell to protect and cover their bodies

Clams, mussels, and scallops produce two shells hinged together – called bivalves

Snails and conchs produce a single shell - called univalves

The clam’s soft body is covered with a thin skin called a mantleOutside of this skin is where material is produced

that hardens to become a shellAs it grows, it adds layers to the shellThe newest part of the shell is thinnest

It also has powerful muscles that keep its shell tightly closedWhen a clam moves, it sends out a muscular FOOTIt is hatchet shaped and is pushed into the sand

and expandedThe muscles contract to shorten the foot and pull

the animal and shell forward

They do not hunt for their foodClams are filter feedersThey dig into the sand and send two tubes

called siphons out to the water. The siphon is used to draw water into the

shell, where tiny food particles are filtered out

The other siphon sends the water away from the clam to remove wastes

1. Name a Mollusk that is edible2. What does an octopus use its siphon to do?3. What part of the clam's body

manufactures its hard shell?

Phylum ArthropodaThe most species of any animal phylumThe insect class is the largest class within this phylumAlmost a million species of insects identified

Many play significant role in our world, especially insects

They serve as:Pollinators, decomposers, crop eaters, disease carriers,

and parasitesAnimals in this phylum have:

Exoskeletons, and jointed appendages such as legs and antennae

Exoskeleton – hard, nonliving, outer covering that supports and protects the animal

Insects typically have three sections to their bodies:HeadThorax (middle part)Abdomen

They also have three pairs of legs (6 total)Caterpillars appear to have more than three pairs,

but actually they are not real legsMost insects have two pairs of wings, although

some may have none or one pairCompound eyes: their eyes have thousands of small

sectionsGrasshoppers see in a mosaic of smaller imagesSee page 286 for picture

Grasshoppers have blood and a circulatory system (like all arthropods)

Blood – is a fluid tissue made up of cells floating in liquid

The main function of blood – to carry substances to and from all parts of the body

Heart – muscular organ that pumps blood to all body cells

Has a series of small tubular hearts located just under its exoskeleton (see explanation p. 289)

Artery – blood vessels that carry blood AWAY from the heart

Open Circulatory System – Blood that does not remain in the blood vessels

The blood is colorless, not redIt carries mostly food and wastes and has little to do

with oxygen transportTracheae – where insects receive oxygen and release

carbon dioxideThey are tiny elastic tubes that branch throughout the

insectAir is pumped in and out of these twenty small

openings called spiraclesInsecticides – chemicals only harmful to insects and

not other living thingsAs blood circulates, it collects wastesThese wastes are filtered out of the blood and

collected by thread-like excretory tubules

Insects go through one of two different life cycles:Some molt throughout their lifeMolting – occurs when insects shed their old

exoskeletons and replace them with new onesThis life cycle is called incomplete metamorphosisMetamorphosis – for insects mean, a change in

body formIncomplete Metamorphism:

Start as eggsGo through a series of molts Developing stages called nymphsThen reach adulthoodExample: grasshopper

Complete MetamorphosisInvolves 4 stages

EggLarva

Most active stageLarvae of moths and butterflies known as

caterpillarsKnown for destructive appetitesOther larvae – maggots (flies) and grubs (beetles)

PupaResting stage where larvae uses food to change

body shapeCocoon (moth), chrysalis (butterfly), puparium

(flies)

Each time one that undergoes COMPLETE metamorphosis and molts, it passes into another stage

Most butterflies die soon after it has matedButterflies do not become bigger butterflies

Not all arthropods are insectsSome are barnacles, crabs, lobsters, shrimp, pill

bugs, centipedes, scorpions, and tarantulasThese differ from insects by the number of body

segments and appendagesCentipedes and millipedes are not wormsCentipedes

FlattenedOne pair of legs per segmentPoisonous claws to kill prey

MillipedesSomewhat rounded bodyCan have up to 100 body segments, and most

segments will have 2 pairs of legsThey are not hunters like centipedes

1. What are the three main parts of an insect's body?

2. What type of eyes do insects have?3. What can we learn from an ant's behavior?4. List the four stages of metamorphosis5. List the three arthropods other than insects6. What sex are worker bees?

Starfish – aka sea stars – are ocean dwelling animals that, along with sea urchins, sand dollars, sea cucumbers, and similar organisms are called echinoderms

Starfish are supported by a system of hard, flat plates just under the skinHard plates and spines provide protectionRadial symmetryArms are called rays

They can regenerate or grow new rays if needed

How do starfish move?Have a water-vascular system that is key to movementNoticeable part of system – rows of tiny tube feet on

the bottom of each ray Tube feet function like tiny suction cups

They stretch out, attach, and then pull itself forward on hard surfaces

Favorite food of starfish – clams Climbs on top of a clam and uses tube feet to pull open

shell (could take hours) Then, turns its stomach inside out and pushed it throuh

the opening of the clam shell Digestive juices digest the soft part of the clam

1. What is the function of the hard plates and spines in a starfish?

2. Where are a starfish's tube feet located?3. What does a starfish not need teeth?